==================================================================
BUG: KASAN: use-after-free in memcpy_to_page include/linux/highmem.h:403 [inline]
BUG: KASAN: use-after-free in z_erofs_transform_plain+0x3a4/0x490 fs/erofs/decompressor.c:346
Read of size 4096 at addr ffff0000fb64c000 by task syz.3.617/7691

CPU: 0 PID: 7691 Comm: syz.3.617 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call trace:
 dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x258/0x290 mm/kasan/generic.c:189
 memcpy+0x48/0x90 mm/kasan/shadow.c:65
 memcpy_to_page include/linux/highmem.h:403 [inline]
 z_erofs_transform_plain+0x3a4/0x490 fs/erofs/decompressor.c:346
 z_erofs_decompress+0x9c/0xd4 fs/erofs/decompressor.c:434
 z_erofs_decompress_pcluster fs/erofs/zdata.c:1159 [inline]
 z_erofs_decompress_queue+0x100c/0x1b40 fs/erofs/zdata.c:1240
 z_erofs_runqueue+0x152c/0x16cc fs/erofs/zdata.c:1603
 z_erofs_read_folio+0x2d8/0x5c8 fs/erofs/zdata.c:1693
 filemap_read_folio+0x134/0x384 mm/filemap.c:2490
 filemap_fault+0x98c/0xe98 mm/filemap.c:3340
 __do_fault+0x11c/0x3d8 mm/memory.c:4278
 do_read_fault mm/memory.c:4629 [inline]
 do_fault mm/memory.c:4758 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x1cac/0x2fb0 mm/memory.c:5292
 faultin_page mm/gup.c:1026 [inline]
 __get_user_pages+0x33c/0x754 mm/gup.c:1250
 __get_user_pages_locked mm/gup.c:1454 [inline]
 get_user_pages_unlocked+0x1b4/0x634 mm/gup.c:2371
 __gup_longterm_unlocked mm/gup.c:2982 [inline]
 internal_get_user_pages_fast+0x1664/0x1a18 mm/gup.c:3072
 get_user_pages_fast+0x60/0x94 mm/gup.c:3164
 madvise_inject_error mm/madvise.c:1122 [inline]
 do_madvise+0x384/0x28e4 mm/madvise.c:1426
 __do_sys_madvise mm/madvise.c:1451 [inline]
 __se_sys_madvise mm/madvise.c:1449 [inline]
 __arm64_sys_madvise+0xa4/0xc0 mm/madvise.c:1449
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:0000000021316c8e refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x13b64c
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 fffffc0003f12708 fffffc0003ed9408 0000000000000000
raw: 0000000000000000 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000fb64bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000fb64bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000fb64c000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff0000fb64c080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000fb64c100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
Soft offlining pfn 0x13c2a3 at process virtual address 0x20001000
syz.3.617: attempt to access beyond end of device
loop3: rw=0, sector=34359738360, nr_sectors = 8 limit=16
syz.3.617: attempt to access beyond end of device
loop3: rw=0, sector=34359738360, nr_sectors = 8 limit=16